1. Chapter 7 Lesson 3 Seed Reproduction
Demonstrate an understanding of sexual reproduction in flowering plants
Describe various methods of plant pollination

2. What You’ll Learn Why It’s Important
Examine the life cycles of typical gymnosperms and angiosperms
Describe the structure and function of the flower
Discuss methods of seed dispersal in seed plants
Why It’s Important
Seeds from cones and flowers produce most plants on Earth

3. I. Importance of Pollen and Seeds
Fruits and vegetables come from seed plants
All plants discussed in lessons 1 and 2 so far are seedless

4. I. Importance of Pollen and Seeds
Some spores develop into pollen grains
a. pollen grains = water resistant covering containing male gametophyte parts the produce sperm
2. Sperm DOES NOT need to swim to female parts.
a. Carried by gravity, wind, water currents, or animals
3. Transfer of pollen grains to female parts = pollination
4. When pollen grains reach female part, sperm and pollen tube are produced.
5. Sperm moves through pollen tube fertilization occurs /

5. I. Importance of Pollen and Seeds
B. Seeds
After fertilization, female part develops into a seed
a. Seed – 3 Parts
(1) Embryo – structure that produces stem, leaves, and roots
(2) Stored food- provided energy to embryo when it begins to grow
(3) Protective Seed Coat
2. Because a seed contains an embryo and stored food, it grows faster than a seed from a spore.
3. Gymnosperms and Angiosperms = seed plants
a.) Gymnosperms develop in cones
b.) Angiosperms develop in flowers and fruits

6. II. Gymnosperm Reproduction
Cones are reproductive structures
Each Gymnosperm species has a different cone
EX: pines, firs, spruces, cedars, ginkgoes, etc.
Spruce Cone
Fir Cone
Pine Cone
Ginkgo Cone

7. II. Gymnosperm Reproduction
Cones
Male and Female gametophyte structures are produced in cones
Pine trees are sporophytes that produce male and female cones
Mature female cones-
Spiral woody scales on short stem
Base of each scale are 2 ovules
Egg is produced in ovule
Pollen grains produced in smaller male cones
4. Spring time- Clouds of pollen released from male cones
Female Cones
Male Cone

8. II. Gymnosperm Reproduction
B. Gymnosperm
Pollen carried from male to female cones by wind
Pollen must be blown between scales of a female cone
a. Here it is trapped in a sticky fluid secreted by the ovule
3. If pollen grain and female cone are same species, fertilization and formation of a seed can take place
4. It takes a long time for seeds to be released from the female pine cone
5. As soon as pollen grain falls onto the female cone until seeds are released could be 2-3 years.

9. III. Angiosperm Reproduction
All angiosperms have flowers
Sporophyte plants produce flowers
Flowers are reproductive organs
Contain gametophyte structures that produce sperm or eggs

10. III. Angiosperm Reproduction
The Flower
4 parts
a. Petals - normally colorful
b. Sepals – outside of the petals (leaf like), form outside of the flower bud
c. Stamen – male reproductive organ (produces pollen)
d. Pistil – female reproductive organ
(ovary is here) – swollen base of pistil
2. Not every flower has all four parts!
EX: Holly Bush
What flower part is missing on a flower from a male holly plant?

11. III. Angiosperm Reproduction
B. Importance of Flowers
Some flowers have large, brightly colored petals – attract insects and other animals
Eat flower, nectar, or pollen
Move about flower – get pollen on wings, legs, and other body parts
Later, animals spread pollen to other plants they visit
2. Others depend on rain, wind, or gravity to spread pollen
Petals are small or absent
Flowers that open at night (cactus flower) have strong scents to attract pollinators
*After pollination and fertilization, ovules develop into seeds

12. III. Angiosperm Reproduction
C. Angiosperm Seeds
Pollen grain reaches stigma in a variety of ways-
Wind
Rain
Animals
2. Angiosperms are pollinated when grains land on sticky stigma
3. Pollen tubes grows from pollen grain down through the style
4. Pollen tube enters the ovary and reaches the ovule
5. Sperm travels down the pollen tube and fertilizes the egg in the ovule
6. Zygote forms and grows into the plant embryo

13. III. Angiosperm Reproduction

14. III. Angiosperm Reproduction
D. Seed Development
Parts of the ovule develop into food and seed coating that surround the embryo.
Some seeds such as beans and peanuts store food in structures called cotyledons
Others have food stored in tissue called endosperm

15. IV. Seed Dispersal Most seeds grow when placed on or in soil
Ways of Dispersal
Gravity
Falls onto soil from parent
2. Wind
Seed has an attached structure that moves with air currents
3. Animals
Eaten with fruits
Passed through digestive system
Dispersed as animal moves from place to place
Stored or buried by animals
Attach to fur, feathers, clothing

16. IV. Seed Dispersal IV. Seed Dispersal
4. Water a. Rain can knock seeds out of dry fruit
IV. Seed Dispersal
B. Germination
Series of events that results in growth of a plant from seed
Some take a few days, others take weeks or months to germinate
**FUN FACT: 1982, seeds of East Indian Lotus sprouted after 466 years.

17. IV. Seed Dispersal
Germination will NOT happen unless environment conditions are right.
Temperature
Presence of light
Availability of water
Amount of oxygen
4. Germination begins when seed tissues absorb water
5. Water causes seed to swell and seed coat to break open

18. IV. Seed Dispersal 4. Series of Chemical Reactions
Releases energy from stored food in the cotyledon or endosperm
Roots grow from the seed, followed by stem then leaves
After plant emerges from the soil, photosynthesis can begin
Photosynthesis provides food as the plant continues to grow